﻿46 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Dec. 4, 



bones, but particularly saurian, are to be found over an area of ten 

 miles ; I have found them in the red shale, in a bluish pale-coloured 

 shale, and in the limestone beds. The bluish shale passes gradually 

 into the limestone beds, and the fossils are similar ; they are, how- 

 ever, very ill preserved in the shale and often recognised with diffi- 

 culty. 



I hope at a future time to be able to give a more minute account 

 of my present locality, Subathoo. 



2. On the Silurian Rocks of Dumfriesshire and Kirkcud- 

 brightshire. By R. Harkness, Esq. Communicated by 

 J. C. Moore, Esq., Secretary G.S. 



In addition to the detrital, superficial deposits of sand, gravel, and 

 clay, the geological formations of the county of Dumfries consist, 

 in descending order, of a red sandstone, the age of which is not yet 

 determined, of coal-fields and carboniferous limestone, and of Silurian 

 rocks. 



The greater part of the county (excepting always many masses of 

 trap rock) is indeed exclusively occupied by rocks which I consider 

 to be of Silurian age, and which cover an area more than twice the 

 size of that possessed by the other formations conjointly. The Silu- 

 rian formation is exhibited in few natural sections, the country over 

 which it prevails consisting in a great measure of comparatively low 

 undulating hills, covered with soil and debris. The course of the 

 rivers, moreover, which drain the district being in a great measure 

 through valleys filled with the newer deposits, it is chiefly in the 

 smaller brooks that such natural sections can be obtained, as afford 

 an insight into the constituents of the Silurian rocks. These and 

 the cuttings of the railways, combined with a few small quarries, are 

 the principal means by which the rocks are exposed ; and conse- 

 quently it requires a considerable extent of country to be traversed, 

 and a number of brook-courses to be examined, before any idea can 

 be formed on the nature and relation of these deposits. 



The term greywacke, as it is generally used, well expresses the 

 mineral nature of the rocks which compose the Silurians of Dum- 

 friesshire, whether these rocks assume a schistose or a granular cha- 

 racter ; but the term slate is totally inapplicable, inasmuch as no 

 true slaty cleavage has hitherto been discovered amongst them. 

 Greywacke is not, however, the exclusive composition of the mineral 

 masses ; for in some localities soft shale, resembling in every respect 

 the shales of the coal formations, is found. Besides this soft shale, 

 beds of anthracite occur ; and so intimate is the connection between 

 the latter and the soft shales, that the one is a constant concomitant 

 of the other. 



Anthracite and Graptolite Schists. 



First Band. — Commencing near the mountain of Hartfell, one of 

 the highest in the south of Scotland, and near the junction of Dum- 



